Photocatalytic hydrogen production with nickel oxide intercalated K4Nb6O17 under visible light irradiation

Nickel oxide nanoclusters were intercalated to layered niobate, K4Nb6O17, to improve the photocatalytic hydrogen production for water splitting under visible light irradiation. A K4Nb6O17–SSRx (Ni/Nb ratio range of 0.8–5%) series of nickel oxide intercalated layered niobates was prepared by a two-step solid-state reaction and characterized by Extended X-ray Absorption Fine Structure (EXAFS), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometer (EDS), X-ray Photoelectron Spectroscopy (XPS) and Ultraviolet–visible spectroscopy (UV–vis). The photocatalytic reaction was carried out in a quartz reactor irradiated under a 500-W halogen lamp. The K4Nb6O17–SSR0.2 catalyst exhibited a much higher photocatalytic activity for water splitting than unloaded K4Nb6O17 catalyst and NiOy/K4Nb6O17 catalyst prepared by the conventional impregnation method. The high catalytic performance was attributed to the well dispersed nickel oxide nanoclusters intercalated into the bulk structure of K4Nb6O17 catalyst and the lack of NiO particles on the external particle surface.